It is pointed out that the term “light” in the expression “light pulses” used in the description herein does not only mean visible light but also include light in a wider spectra, as for instance light and certainly also infrared light, but is hereafter only referred to as “light pulses”.
Such a system and method may be used for transmitting all types of information, such as fired ammunition type or other parameters relating to the condition of said first player, but for illustrating the present invention and the problem to be solved thereby such transmission for determining scoring of simulated firing of said first player, i.e. whether a projectile fired by the first player has hit a said second player or not, will hereinafter be described in a non-limitative way.
Although the specification herein refers to first and second players it is pointed out that both players may have the same equipment and may be regarded as first and second players, and there may be many such similar players participating in said training area.
When a said first player is shooting towards a said second player, which may be a tank, another vehicle, a soldier, a building, etc. at a relevant distance, it may be necessary to consider the ballistics of the projectile or the missile trajectory when determining the location of the hit point with respect to said second player. However, said light pulses are traveling in a rectilinear path, so that it is not possible to decide where the hit point is located with respect to said second player when only the recti-linear characteristics of said light pulses are used by said players for determining the hit point. For instance for a tank it is necessary to at least know the aiming direction of the gun relative to said second player, the projectile path characteristics as well as the distance between said players when determining whether the hit point is located on a said second player or not.
U.S. Pat. No. 4,218,834 describes a military training system for scoring a simulated weapon firing, and this system has reflectors arranged on possible targets, such as said second players, for reflecting said light pulses back to said first player, which may then use the travelling time of said light pulses for calculating the distance between the first player and a second said player. However, such reflectors put on possible said second players are somewhat costly.
The simplest form of simulation is to only transmit a pulse coded rectilinear light beam and when said second player detects these pulses they may be evaluated as a hit. There is not any ballistic flight path considered and a simple form of hit position determination may only be done by having a number of detectors on said second players, in some weaponry training areas there may simultaneously be players with ballistic and rectilinear simulator equipment. The latter are usually personnel because of several reasons like the requirement for lower weight, less power consumption and lower cost.
U.S. Pat. No. 6,386,879 describes another system and method of this type having no reflectors. The distance between said first and second players is determined by comparing the players GPS positions. This information together with ammunition type and other data is transmitted instantly at time of fire and then said second player computes an impact position and effect on target. This requires that said second player knows GPS data and other player data of said first player which significantly increases the number of light pulses, that has to be transmitted by said first player and correctly received by the second player.
The type of simulation defined in U.S. Pat. No. 4,218,834 is usually applied as a real time type of simulation as the sweeping fan shaped beams usually follows the simulated flying projectile during its time of flight and finally when the said first player receives reflections from a said second player at the same distance as the simulated projectile, the data is transmitted.
The said rectilinear path type of simulation on the other hand usually makes an instant transfer of data at time of fire to the said second player. Both real time type and instant type of simulator systems require more or less data to be transferred to the said second players. There are many parameters that are influencing light pulse transmission concepts for sending information between said players to be as error free as possible and some examples are given here. The transmitter intensity and transmission duration are limited because of safety regulation limits. There are several reasons why the transmission of information may be disturbed. For instance the atmospheric influence may fluctuate from for instance weather conditions, strong sunshine may influence the said light pulse detector sensitivity and sometimes there are thermal air turbulences reducing the number of received aid light pulses in a transmission. The total available error free time to transmit may be very short especially if the transmitter has not a stable direction during the data transmission. This makes it necessary to keep the number of said light pulses in light pulse transmission protocols to a minimum, still being able to transmit with enough redundancy that losses of said light pulses does not cause any data loss. The method of this invention provides a previously unknown possibility to use a minimum required light pulses to be transmitted.